Thanks for looking - and helping if you are able-

I currently have a crate engine in my car. The previous owner swears it is a 330hp GM crate engine from Summit Racing, but the only 330hp engine I could find over there has Vortec heads, and mine have 6 intake bolt holes, so I don't see how these could be Vortec heads. I have seen some Vortec heads with 6 bolt holes, but the cast also had "Vortec" molded into it. Perhaps there are other versions of the Vortec? My casting # is 462624.

So, here is what I have

You can see that the intake ports are not square, but they are wider at the bottom with a little notch left in at the top corner - obvious in this photo

When I put the Edelbrock intake gasket for my Performer RPM intake (6-bolt), it matches right up

When I put the same gasket on the heads, they don't line up so well and look like this (making me think they are not correct for these heads

My questions:
1- Can this possibly be a Vortec, or some other head?
2- Could this head (casting 462624) possibly have been on a high performance GM crate engine?
3- Why such a big difference in port size/shape between the Edelrock intake ports and the GM head ports? Is the difference normal?

Thanks for any help. I want to make sure I am using the right gasket this time because the last one had a bad leak.